How fastening technologies can help overcome EV range anxiety

Many engineers already know that one of the earliest World Land Speed Records was set by an electric car, when the Belgian driver Camille Jenatzy took his bullet-shaped vehicle Le Jamais Contente to 100kph. In those days (1899), this was a fantastic speed and in 2018 the outright world speed record for a battery-powered car stands at well over 300mph. However, today’s EV engineers are driven by consumer demand and focusing more on range and durability than outright speed. As EVs have evolved for public consumption, a new phrase has entered the conversation and it is said to reflect the biggest reason why the buying public continues to resist the current crop of extremely competent EV offerings. ‘Range anxiety’ is still proving a difficult challenge to overcome for manufacturers and a genuine ongoing concern.

With battery technology sometimes said to be holding back the rest of the EV package, attention has been focused on maximising the power available in other ways to improve the range and battery duration. Amongst the many effective ways of tackling the challenge, weight reduction has emerged as a key aspect in the quest for more miles and smiles per amp. So, advanced materials, including plastics, composites and lightweight alloys, have been at the forefront of EV development, (just as they have in the quest for more mpg from petrol and diesel vehicles) and things look set to remain that way for the foreseeable future. But as new materials and methods of forming them have been trialled and either improved, approved or discounted for EV use, engineers have become increasingly aware that the process of putting them all together, or attaching necessary parts to them, has become more of a challenge.

This has been especially true of components which the EV manufacturer chooses to join by using threaded fasteners – because incorrectly torqued nuts and bolts can cause significant problems. Nuts and bolts tend to work loose if they are done up to a level below the specified value; but if they are installed too tightly they can deform the parent material, with potentially expensive and problematic results. To this end, Bridgnorth-based Fitsco Industries has been busy developing a new range of compression limiters for use with threaded fasteners in plastics and composites, with some of the products already being tested by EV manufacturers. The compression limiter is a non-threaded device fitted between the head of the fastener being tightened down and the top surface of the host material that the fastener is being put into. Installing a compression limiter helps to prevent cracking and creeping in the host material as the fastener is torqued down and thus assists in maintaining the integrity not just of the individual joint itself, but the overall integrity of the complete part.

Delivering performance

Sensibly, compression limiters can be installed either pre- or post-moulding and Fitsco can also provide users with a ‘Poka Yoke’ solution to help speed up assembly times on the shop floor. In the EV environment, Fitsco states that its compression limiters are proving useful in both body and chassis applications. For applications in firmer plastics and composites, such as structural members, it encourages manufacturers to opt for the ‘standard’ compression limiters. However, for the many non-structural applications that involve fastening into softer materials – for example, those which might be rubber based – the innovative Fitsco ‘Headed’ compression limiters are said to be better suited. This, says Fitsco, is because they spread the load over a wider surface area to deliver the required performance.

All Fitsco compression limiters are manufactured at the Company’s factory in Shropshire to stringent ISO9001-2015 standards and are available with plain, grooved or knurled outers to suit most applications. The company has application specialists on hand to provide free assistance.

Fitsco CEO Philip Schofield says: “The UK continues to lead the field in automotive R&D and we’re involved in a number of exciting projects at the moment, some of them with EV manufacturers. Because we are a UK manufacturer selling UK-made fastening solutions, we’re always on hand to assist where we can in our chosen area of expertise. Fastening into plastics and composites appears to be a simple task at first glance, but, as many engineers have already discovered, it is another field where expert assistance and knowledge can have a dramatically positive effect!”